A digital signature generally provides a mechanism for a receiver of a digital message to have confidence that the message was in fact sent by a purported sender. A digital signature can function analogously to a traditional handwritten signature. Digital signatures can provide non-repudiation and time stamping to prevent the sender from denying that they sent the message, and possibly also to prevent the sender from disputing the time that the message was sent. Digital signatures are generally based on cryptographic mechanisms. For example, digital cryptographic keys may be used to sign a digital message with a digital signature. The digital message can include any digital information.